1. Field of this Invention
This invention relates to a process for the production of 2-amino-4-hydroxy-6-methylpteridine from 2,4,5-triamino-6-hydroxypyrimidine and 1,1-dichloroacetone.
2. Prior Art
The production of 2-amino-4-hydroxy-6-methylpteridine via 2-amino-4-chloro-5-phenylazo-6-hydroxypyrimidine [Boon, Leigh, J. Chem. Soc., (1951), 1497] or via pyrazine derivatives [Taylor, J.A.C.S., 95, 6407, (1973)] free of isomers. These processes are however uneconomical since they are based on several, in part complicated, synthesis steps.
Other production methods are based on the cyclization of 2,4,5-triamino-6-hydroxy pyrimidine, made from quanidine and ethylcyanoacetate with acetoxyacetone [Viscontini, Helv. Chim. Acta, 54, 811 (1971)] or pyruvate aldehyde [U.S. Pat. No. 2,477,426 and Storm, J. Org. Chem., 36, 3925 (1971)]. The acetoxyacetone and pyruvate aldehyde however are extremely unstable and therefore can be used only with difficulty in the execution of the reaction. In the case of such processes there is the additional difficulty thatmixtures of almost unseparable 6- and 2-amino-4-hydroxy-7-methylpteridine result.
Another process [King, Spensley, J. Chem. Soc., 2144, (1952)] describes the production of 2-amino-4-hydroxy-6-methylpteridine by reaction of 2,4,5-triamino-6-hydroxypyrimidine with 1,1-dichloroacetone. However, when such process was conducted by applicant, mostly undesirable 2-amino-4-hydroxy-7-methylpteridine was obtained.